Like some players I too suffer from input lag making my mouse move sluggish in high action, I've tried the usual "fixes" and they only slightly helped, But the solution that helped me was setting the game to use 3 processor cores affinity (im using quad core) and my inputs are perfect, the only downside is fps dips a little bit (but im running a gtx670 so you guys might not even get fps drops). tldr: Set the game processor affinity and uncheck a core, should stop the game from hogging cpu usage for better input stability. I hope this really helps others.